Validation of an HPLC method for estimation of cefotaxime from dried blood spot: alternative to plasma-based PK evaluation in neonates

Aim: Pharmacokinetic evaluation of cefotaxime in neonates is currently a challenge due to the large volume requirement of blood for its analysis by existing methods. A dried blood spot (DBS) based method is the best alternative. Materials & methods: We validated an HPLC method for estimation of cefotaxime from DBS and plasma. Extraction employed a simple procedure using acetonitrile and buffer. Selective separation of cefotaxime was achieved on a C8 column using gradient programming. Results & conclusion: The linearity of the method ranged from 2 to 200 μg/ml with acceptable precision and accuracy for both plasma and DBS. Hematocrit was not affecting the assay accuracy. A strong correlation and interchangeability observed with the plasma method proves its clinical validity for application to PK evaluations. Cefotaxime is a widely used antibiotic in the neonatal population for treating bacterial infections. At the same time, determining the dosage for this antibiotic in the vulnerable population is always a challenge for the treating doctor. In the case of neonates, organs are not fully developed and their response to drugs will be different from that of adults. In the current clinical practice, dosage for neonates is deduced from pediatric dose without addressing this difference in the response. The major challenge in addressing this issue is the collection of blood by venipuncture from neonates for drug analysis. In this report, a microsampling technique called dried blood spot is used for sampling and bioanalysis of cefotaxime. The method is validated for estimation of cefotaxime from the neonatal blood.